We are analyzing the pathogenesis of a number of selected neurological and neuromuscular mutants in mice with the hope that the knowledge gained may clarify mechanisms of human hereditary neuromuscular diseases. The overall goals of these studies are to achieve an understanding of the primary gene effect(s) and underlying mechanisms leading to each of the mutant syndromes. Mutantions under investigation are qk (quaking), jp (jimpy), and its allele jpmsd (myelin synthesis deficiency) representing disorders of myelin metabolism and also several recently discovered neurological mutations whose defects are as yet unknown. BIBLIOGRAPHIC REFERENCES: Tsuji, S., A. D. MacPike, E. Ohkouchi, and H. Meier. 1975. Genetic relationship of two mutant genes producing three different syndromes in the mouse. Exp. Anim. (Jap) 24:111-118. MacPike, A. D., and H. Meier. 1976. Genotype dependence of monoamine oxidase in inbred strains of mice. Experientia (in press).